Viral outbreaks in neonatal intensive care units: what we do not know.

Background: Nosocomial infection is among the most important causes of morbidity, prolonged hospital stay, increased hospital costs, and mortality in neonates, particularly those born preterm. The vast majority of scientific articles dealing with nosocomial infections address bacterial or fungal infections, and viral agents are often disregarded. This analysis reviews the medical literature in an effort to establish the incidence, types of pathogens, and clinical features of noncongenital neonatal viral infections. Methods: This analysis was performed using the worldwide database of health care-associated outbreaks (http://www.outbreak-database.com). Items analyzed included causative pathogens, types of infection, source of outbreaks, and measures taken to stop outbreaks. Results: The outbreak database contained a total of 590 neonatal outbreaks, of which 64 were originated by viruses, 44 of which (68.75%) were reported from neonatal intensive care units (NICUs). The 5 most frequent viral agents were rotavirus (23.44%), respiratory syncytial virus (17.19%), enterovirus (15.63%), hepatitis A virus (10.94%), and adenovirus (9.38%). Conclusion: Our analysis of the viral origins of nosocomial infections in NICUs can be a valuable tool in the investigation of neonatal infections. The mortality rates reported in this analysis demonstrate the significance of noncongenital viral infections in NICUs and the need for more effective outbreak prevention strategies.